1.1 这些测试方法包括1378厘米红外吸收分光光度法的测量 −1. 由于甲基的存在，聚乙烯中出现（7.25μm）条带。 ( 1. , 2. , 3- 6. ) 2. 包括两种测试方法: 1.1.1 试验方法A 使用已知甲基含量的标准样品膜进行补偿。 1.1.2 试验方法B 使用聚甲基丙烯酸甲酯楔块或已知甲基含量低的聚乙烯进行补偿。 1.2 这些试验方法适用于I型聚乙烯（密度0.910至0.925 g/cm 3. )，II（密度0.926至0.940 g/cm 3. )和III（密度0.941至0.965 g/cm 3. ). 注1: 关于密度的测定，请参见规范 D1505型 . 注2: 对于密度大于0.950 g/cm的III型聚乙烯 3. ，两种试验方法得到了不同的结果。 1.3 以国际单位表示的数值应视为标准值。括号中给出的值仅供参考。 1.4 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 具体危险说明见第节 7. . 注3: 没有已知的ISO等同于本标准。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 =====意义和用途====== 4.1 当借助适当的校准数据进行解释时，任何一种测试方法都可以用于比较类似工艺制备的聚乙烯的总甲基含量。某些其他波长的红外吸收数据可能对某些其他波长信息有用 ( 7. ) . 注4: 总烷基浓度的测定偏差取决于所存在的甲基和乙基支链的浓度，因为这些支链在1378 cm处具有异常高的每组吸收率 −1. （7.25微米）。 4.2 当结合分子量和反应性端基（如乙烯基）的数据时，聚乙烯中总甲基的知识可能有用，以便进行端部分配- 基团结构并阐明聚合机理。 4.3 聚乙烯中总甲基的数据与某些聚合物特性（如熔点、密度、刚度和其他机械特性）之间可能存在定性关联，这些特性与聚合物的结晶度密切相关。 4.4 这些测试方法特别适合于研究。它们尚未在制造控制中进行测试。

1.1 These test methods cover measurement by infrared absorption spectrophotometry of the 1378 cm −1 (7.25 μm) band in polyethylene due to methyl groups. ( 1 , 2 , 3- 6 ) 2 Two test methods are covered: 1.1.1 Test Method A uses compensation with a standard sample film of known methyl content. 1.1.2 Test Method B uses compensation with a wedge of polymethylene or a polyethylene of known low methyl content. 1.2 These test methods are applicable to polyethylenes of Types I (density 0.910 to 0.925 g/cm 3 ), II (density 0.926 to 0.940 g/cm 3 ), and III (density 0.941 to 0.965 g/cm 3 ). Note 1: For determination of density, see Specifications D1505 . Note 2: In cases of Type III polyethylene with densities greater than 0.950 g/cm 3 , different results are obtained with the two test methods. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific hazards statements are given in Section 7 . Note 3: There is no known ISO equivalent to this standard. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 When interpreted with the aid of appropriate calibration data, either test method is acceptable for use to compare the total methyl contents of polyethylenes made by similar processes. Data on infrared absorption at certain other wavelengths is potentially useful for information on certain other wavelengths ( 7 ) . Note 4: The bias of determination of the concentration of total alkyl groups depends on knowing the concentrations of methyl and ethyl branches present, since these branches have anomalously high absorptivities per group at 1378 cm −1 (7.25 μm). 4.2 Knowledge of total methyl groups in polyethylene, when combined with data on molecular weight and on reactive end groups such as vinyl, is potentially useful so as to lead to assignment of end-group structures and to shed light upon polymerization mechanisms. 4.3 Qualitative correlations are possible between data on total methyl groups in polyethylene with certain polymer properties such as melting point, density, stiffness, and other mechanical properties that are closely dependent on the degree of crystallinity of the polymer. 4.4 These test methods are especially suitable for research. They have not been tested for use in manufacturing control.